Inserting more than one image over image

I am a newbie creating a newsletter using tables and inline css, the problem is that i need to insert more than one image over an image(not background)... can anybody suggest me some possible solutions..

Breif :
1. I have inserted a background image
2. Then i inserted a image on it
3. Now i need to insert another image onto it

You can change the location of the second image using position: relative and setting the left and top margins to the correct values so the images lie over each other (negative values are allowed). The z-index CSS attribute allows you to layer two elements over each other. The higher the z-index the more to the top the element is (i.e. a z-index of 10 will appear over an element with a z-index of 4).
So, if you had 2 images side by side on the page and wanted the right one over top of the left by 50px, the css would be

i can understand it, but even that is not supported by gmail, and android. I have added a link to check the compatibilty.. check it.. so that you can have a better understanding of my situation http://www.campaignmonitor.com/css/